In recent years, a growth in demand for storage batteries is expected especially in the field of electric cars. Further, storage batteries are also attracting attention in relation to the use thereof as stationary batteries. Particularly, attention is focused on the use of storage batteries for the purpose of emergency power supply, leveling of charge demanded as a result of introduction of renewable energy, and energy conservation devices which promote efficient use of energy. The use of storage batteries widely varies from V2H (vehicle to home) to the recycling of the storage batteries, and it is considered that the storage battery-related business will attract further attention in the future.
The stationary storage batteries known today are used in a manner such that a whole battery pack is fixed on a system via welding etc. On the other hand, as a means for effectively utilizing a large secondary battery, the battery may be provided as a battery cartridge system. The cartridge system means a system where a battery is replaceable or is a part which can be easily replaced, and the battery is portable. For example, when a storage battery for home use is provided in the form of a battery cartridge system, it may be used as an extender for electric cars where the maximum driving distances largely vary depending on the driving conditions. Or when such a battery cartridge system is used for a bicycle, the time for charging the battery can be omitted thereby improving the convenience of the use of the bicycle (see, for example, Prior art document 1).
A battery cartridge system is also advantageous in that, when it is intended to change the amount of domestic power use, the power supply can be increased easily and that with a high economy because the introduction of a new system is not necessary. Furthermore, a large storage battery such as used at community level or plants can also be provided in the form of a cartridge system, whereby only deteriorated battery packs can be replaced so that the maintenance and renewal of the entire system become easy, thus providing a high economic benefit.